Apparatus for twisting threads



Oct. 23, 1951 G NSALVES 2,572,135

APPARATUS FOR TWISTING THREADS Filed Jan. 11, 1949 an n INVENTOR. W Conrad Joseph Gansalres:

Arm/va Patented Oct. 23, 1951 APPARATUS FOR TWISTING THREADS Conrad Joseph Gonsalves, Arnhem, Netherlands, assignor to American Enka Corporation, Enka, N. 0., a corporation of Delaware l nlicatlon January 11, 1949, Serial No. 70,242 In the Netherlands April 13, 1948 8 Claims. (CL 57-74) The present invention relates to a method and apparatus for twisting and winding threads into package form and more particularly to a captwisting device that during the twisting operation progressively increases the tension on the thread in its path of travel through the twister in order to maintain the winding tension substantially uniform throughout the twisting operatibn.

The normal cap-twisting device consists of a simple cap that surrounds a bobbin which is reciprocated vertically with respect to the cap. The thread to be twisted is drawn from a suitable source through a thread guide positioned above the device, and passes in the form of a balloon around the lower edge of the cap onto the rotating bobbin and is traversed axially thereof as a result of the relative reciprocation. The degree of twist in the thread depends on the ratio between the R. P. M. of the bobbin and linear speed of the thread.

These well known cap-twisters are subject to two drawbacks. The first occurs when, during initiation of the twisting operation, the thread does not form a ballon but slides over the surface of the cap thus creating an undesirable pretension. This, plus the tension created at the lower edge of the cap as a result of the radial component of the force acting on the thread passing to the empty bobbin, causes a still further increase in the overall tension on the thread which may even reach such magnitude as to cause thread breakage. 4

Then, after the twisting operation has commenced and the pretension has disappeared as a result of the ballooning of the thread, another diiliculty is encountered. The radial component of the force acting on the thread decreases as the package builds up, whereby the winding tension decreases and the package, as it is formed, is rendered insuihciently hard for practical purposes. Since the thickness of the thread body increases during the twisting operation, the direction of the thread in its path of travel between the edge of the cap and the bobbin undergoes a change. It is obvious that the initially radial direction of the thread changes progressively to a tangential direction, and consequently the-friction on the edge of the cap decreases. In the final analysis the result is that the winding tension decreases and the thread package becomes progressivelv softer from the inside to the -outside. If this is continued too long, it may become necessary to interrupt the twisting operation beioreit is completed when the package is still too small from the standpoint of economical operation.

Summarizing, when using the normal cap twisters, it is either w; 1 to utilize a bobbin having a diameter approaching that of the cap, or the winding operation has to be terminated prematurely. In either case, the thread package obtained does not have suillcient body and does not possess a uniform hardness.

Several attempts have been made to overcome the above mentioned diillcultie's, but none have been completely-successful. One such attempt involved the use of a so-called ring and traveler arranged on the bottom edge and if desired the top edge of the cap. This ring and traveler equipped with a projecting sliding edge maintained a distance between the thread and cap. which regulated the tension during the twisting operation for a short time, but was not sumcient to ofiset the decrease in tension as the twisting operation proceeded.

U. S. Patent No. 2,331,200 attempted to overcome the problem by providing an auxiliary ring mounted in arcuate slots near the bottom portion of a cap twister. This ring moved vertically downwardly asthe twisting operation proceeded and it was stated that this had the eiiect of increasing the diameter of the lower edge or the spinning cap which increased the radial component of the direction or the thread passing over the lower edge. which in turn, increased the tension of the yarn being delivered to the bobbin. However. the difliculties were not sufliciently overcome because merely increasing the diameter of the lower edge of the cap without introducing any further friction points of contact with the thread, was inadequate.

It is an object of the present invention to pro vide a method of increasing the pretension on the thread during the twisting operation in such a way that the tension under which the thread is found on the bobbin is maintained substantially uniform.

A further object of the invention is the provision of a frictional tension on the thread in addition to the friction created between the thread and the lower edge of a twister cap.

This invention also contemplates a cap twister which is provided on its exterior near the bottom edge with a tension ring.

An additional object or the'invention is to provide a normal ring twisting device with an adjustable tension ring that encompasses the cap twister near the bottom portion thereof ,and moves downwardly with respect to the cap twista 3 er during the twisting operation in order to progressively increase the pretension on the thread as it passes under the tension ring and over' the lower edge of the twister cap.

Another object of this invention is the provision of one or more guiding rings fixed to the outside of the twister cap in order to prevent objectionable tension on the thread during the initiation of the twisting operation.

Other objects and advantages of this invention will become apparent from the following detailed description when considered in conjunction with the accompanying drawings, wherein:

Figure 1 is an elevation in partial section of a preferred embodiment of the invention showing the tensioning ring in operative position at the beginning of the twisting operation;

Figure 2 is an enlarged sectional view showing the thread passing around the toe of the spinning cap and under the edge of the tension ring;

Figure. 3 is an enlarged sectional view of a modified form of twister cap and tension ring; v

and

Figure 4 is a plan view of a section of the tension ring showing a chordwise slot passing from the outside of the ring to the inside thereof in a direction similar to that of the passage of the balloon around the ring so that the thread cannot escape during the twisting operation.

Referring to the drawings, and more particularly to Figure 1, there is shown a collecting bobbin III, which is mounted on a spindle rail II. This spindle rail H is reciprocated vertically from below by anysuitable means, not shown. The bobbin III is rotated at the desired R. P. M. by means of spindle whorl l2 operated by belt l3. Reciprocation of the bobbin III is efiected about stationary spindle H, which spindle also supports twister cap [5 in a stationary manner so that there is relative vertical reciprocation between the bobbin l0 and the twister cap I5.

Surrounding the lower portion of cap [5 is a tension ring I6 which is connected by shaft I! to a clamp it, which in turn is fixed to rod I9. Rod I9 is mounted for vertical reciprocation in bearings 20. A roller 2| is fixed to the lower end of rod l9 and rides on cam 22. As cam 22 is rotated in a counterclockwise direction from the Figure 1 position, the rod l9 moves vertically downwardly as a result of the roller 2| following the cam path which draws closer to the axis of the cam until the twisting operation is completed.

The cam 22 is driven during the twisting operation at a speed correlated with the size oi the package to be twisted, by any conventional mechanical means not shown. Since the cam is of the half-cycle type it is apparent that some resetting mechanism such as the free-wheeling clutch is necessary so that the cam may be reset to starting position at the termination of the twisting operation.

When a package is to be formed, thread 23 is drawn from a source of supply, not shown, and passed by means oi a feed roller, not shown, through a thread guide 24 located above the twisting device whereafter it is led under tension ring Hi and over the lower projecting edge 25 of cap l5 to the bobbin l0.. Between the guide 24 and the tension ring it the thread forms a balloon as a result or centrifugal force created by the rotation of the bobbin.

lit the initiation of the twisting operation, the tension ring is in its highest position with respect to the lower edge 25 of the cap I5 (see Figure 1). This, in the first phase 01 the twisting,

constricts the balloon and creates only a low pre-tension on the thread between the ring I8 and lower edge 25. This is desirable because at this stage the highest tension exists on the thread at the lower edge 25 due to the magnitude of the radial component of force acting on the thread passing to the empty bobbin.

As the twisting proceeds the ring 16 moves downwardly due to the synchronized rotation of the cam 22. The pre-tension thereby progressively increases to offset the diminishing tension on the thread at the lower edge 25 of the cap [5 due to the decrease in radial component force as the thread package builds up. Therefore the overall winding tension is maintained substantially constant throughout the twisting operation. When the bobbin has been filled with thread,'the cam 22 can be turned clockwise to the starting position for the next winding operation.

As a further precaution against the creation of undesirable tensions at the start of the twisting, guiding rings 26 and 21 are provided on the outside of cap 15 at the top and center thereof. These rings guide the thread only until the balloon forms, after which the thread no longer touches them. The guiding rings 26 and 21 have an outer diameter which is preferably less than the inner diameter of the tension ring I6 so that the tension ring can be constructed in one piece and still be fitted over the top of the cap l5 to thereby encompass the same. Since the lower edge 25 has a greater diameter than the inner diameter of tension ring Hi, it is not possible to assemble the ring around the cap [5 from below.

-In Figure 2 there is shown an enlarged sectional view of the thread passing around the L-shaped lower edge 25 and under the tension ring l6 whereby a positive tension is imposed on the thread at two points.

The modification shown in Figure 3 involves the use of a specially shaped tension ring having a nose 28 and the L-shaped lower edge of the spinning cap is provided with a double sided toe 29. This structure is utilized when it is desirable to have a particularly high pro-tension on the thread during the latter part of the twisting operation at which time the nose 28 is in the position indicated by the dotted lines in Figure 3.

In order to facilitate the threading-in of the thread when the twisting operation is initiated, the tension ring I6 is provided with a chordwise slot 30 passing from the outside of the ring to the inside thereof in a direction similar to that of the passage of the balloon around the inside of the ring (see Figure 4).

What is claimed is:

1. In apparatus for twisting thread involving the use of a collecting bobbin and a twister cap together with means for causing relative reciprocation therebetween, and a thread guide positioned above the cap, the improvement which comprises means interposed between the lower edge of the twister cap and the thread guide positioned above the cap for tensioning thread and means for moving said tensioning means to progressively increase this tension during the twisting operation.

- 2. In apparatus for twisting thread involving the use of a collecting bobbin and a twister cap together with means for causing relative reciprocation therebetween, the improvement which comprises a tension ring surrounding the lower portion 01' the cap for tensioning the thread prior to its passage around the lower edge of the cap and means for moving the ring vertically to pros gressively increase this tension during the twisttension ring for moving it downwardly during thev twisting operation.

4. An apparatus according to claim 3 which further includes means for preventing excessive tensions in the thread during the initiation of the twisting operation.

5. An apparatus according to claim 4 in which the tension ring is provided with a chordwise slot to facilitate threading up of the device.

6. In-apparatus for twisting thread involving the use of a collectingbobbin and a twister cap together with means for causing relative reciprocation therebetween and means for delivering thread thereto, the improvement which comprises a tension ring surrounding the lower portion of the cap for'tensioning the thread prior to its passage around the lower edge of the cap, a cam and roller assembly connected to the tension ring for moving it downwardly during the twisting operation and means to rotate the cam at a speed correlated with the size of the package to be twisted.

CONRAD JOSERH GONSALVES.

REFERENCES CITED The following references are of record in th file of this patent:

UNITED STATES PATENTS Number Name Date 815,075 Doll Mar. 13, 1906 FOREIGN PATENTS Number Country Date 445,010 Germany June 1, 1927 

